Optical zone marker



FIG. 1 is a side elevational view of an optical zone marker showing my new design;

FIG. 2 is a rear elevational view of the marker;

FIG. 3 is a front elevational view of the marker;

FIG. 4 is a top plan view of the marker; and

FIG. 5 is a bottom plan view of the marker. 

The ornamental design for an optical zone marker, as shown and described. 